But the Celtic manager is delighted to say he has answered him in the most positive way possible.
Commons is now one of the first names down on his teamsheet for crunch games like next week's Group H home tie against Ajax, the first leg of a double-header which seems certain to determine if the Hoops will be playing European football after the turn of the year.
He has already made his mark at this level, most notably when scoring the penalty which saw Celtic defeat Spartak Moscow and book their place in last season's last 16.
The 30-year-old surprised everyone when, after nervelessly stepping up to take the spot-kick in the final group game, revealed he didn't know that scoring would see them beat Benfica in the race for qualification from the group along with Barcelona.
Neither did he know his performances throughout the run had answered a question which Lennon had posed to himself right at the start of the campaign.
Sure, Commons had been a huge hit for the club at domestic level since moving to Parkhead for a bargain £300,000 in January, 2011.
But, Lennon admits he still harboured concerns that the squat-built attacking midfielder's qualities were going to transfer effectively to the European stage.
The Parkhead boss explained: "Kris has surprised me because he has taken his career on and, the older he is getting, the better he is getting. I had a doubt whether he could play at Champions League level. But, he has answered all those questions as well."
Lennon took almost a full team of Champions League rookies into the group stage 14 months ago, and knew it was only when they went toe-to-toe with some of football's elite that he would discover if they had what it takes to compete at that level.
Commons was such an important cog in the Green Machine he had built. But, could he function when put under the intense pressure that comes with Champions League football?
"Last year, going into the games, I was thinking, did Kris have the legs? Did he have the pace? And he answered all that in spades," a delighted Lennon is now able to report.
"He had an exceptional campaign and, again, I think he has played very, very well in Milan and at home against Barcelona in our opening two group games this season."
Coming off the back of a poor second season at the club, when injury and a drop in form was in stark contrast to the instant impact he had made in the four months he played after his arrival, that was a very big bonus for Lennon and the Celtic team.
It was also enough to earn Commons a recall to the Scotland squad. But, after deciding he wanted to spend more time with his wife and young family, Commons called time on his international career.
Recently, he has spoken about reviewing that decision, although it has yet to be seen if he will make the call to Gordon Strachan.
Although a good friend, and in regular contact with the Scotland boss, Lennon is not becoming involved in this matter.
Quizzed whether he believes Commons' club form has improved because he has stepped away from international duty and is now getting more free time to recover and spend time with his family, Lennon diplomatically answered: "You would need to ask Kris that."
Lennon is much more forthcoming when he turns his attention to how Commons was playing prior to the international break.
"I thought, on the ball against Barcelona, he was our best player," said the Celtic boss. "His technical ability is unquestioned.
"And, in our game against Motherwell before we stopped for the international games, I thought he was just fantastic, so intelligent.
"It was not just with his goal - though that was a thing of beauty and exceptional - but his all-round game. He is in a great place and is a great player."
One who will report back for business this week ready to go again, with Saturday's league match against Hibs at Easter Road the warm-up match before Ajax come to Glasgow next Tuesday.
While Lennon knows Commons is fit and raring to go, he will have to check on the condition of all his international players when they eventually get back to Lennoxtown, some with World Cup places booked, others with hard-luck stories to overcome.
Mikael Lustig is already a doubt for the weekend after suffering a recurrence of a hip problem when playing for Sweden last Friday.
It is always an anxious time for the Hoops boss, but especially so with such important Champions League games on the near horizon.
Perhaps, as some form of distraction, he is considering taking in an international tonight, and might even venture a bit further than Hampden where Scott Brown and Charlie Mulgrew will be lining up against Croatia.
Lennon is already working on adding to his squad in January, and such games can shine a light on potential targets.
If he can land another bargain buy like Commons, he will be delighted.