Lacazette scored his seventh Premier League goal of the season after just four minutes of the 5-0 win over Huddesfield with a clinical finish.
But the France striker picked up a knock midway through the first half and was substituted at the break with Olivier Giroud coming on in his place.
In his absence, Giroud scored twice as Arsenal crowned off a fine display.
The Gunners travel to Manchester United on Saturday.
But Lacazette appears unlikely to play after Wenger suggested he is set for a spell on the sidelines.
“It is an injury, it looked like a groin injury so he might be out for a while,” Wenger said.
On the game he added: “The last 20 minutes became comfortable but I would say Huddersfield did fight very well.
“In the second half I felt at some stages it could have been 1-1 but when we scored the second goal the game changed completely.
“We played very well, with freedom. We played a bit on the edge before that.”
Alexis Sanchez and Mesut Ozil also got on the scoresheet for Arsenal.
And midfielder Aaron Ramsey praised his side’s display against a battling Terriers.
“Full credit to Huddersfield, they made it difficult for us to break them down. We upped the tempo in the second half and were more clinical,” he said.
“Mesut Ozil was ill for the Burnley game but his batteries were recharged and he was fantastic tonight.
“We wanted to take advantage of being at home and we did that again. It is another three points and hopefully now we can go into the Manchester United game at the weekend full of confidence and hopefully it will be a very successful week for us.”
