He was prepared to stay at Arsenal until the Lacazette rumours started. Arsenal are in the same European competition as us.
He was/is happy at Arsenal (maybe even as a squad player) if he decides to move on, he will (IMO) be looking for a champions league club because there will be a few takers, and he's 31 soon.
Also, just because Arsenal are in the Europa league doesn't mean he would be happy to join us because we're in it.