The Gunners needed a home win to progress to the Europa League final, but could only draw 0-0 after having lost the first leg 2-1.
Lacazette, who was not fully fit ahead of the game, did not come on until later in the second half.
Asked by reporters if he could have come onto the pitch at half time, Arteta said, per football.london: "No. He was only available to play 10 minutes. 15 minutes maximum.
"We were already taking a risk because he hasn't trained fully with the team.
"But he wanted to take that risk and we believed that it was worth taking it. That's the maximum that he could play."