[Jeffage]

Check the turn - he may have beaten you with that card or possibly had you beat already. And your check may induce a bluff on the river from him. If you do bet the turn, I think you have to fold to his raise.

Edit to add: If he has JJ or something similar he has two outs and may very likely fold the turn bc the ace means you got there if you weren't already ahead. Your check will cause a laggy player to bet the river or at the very least check call, gaining you an extra bet.

Jeff