It clearly does matter to you, so there is no shouldn't here. Perhaps you could ask yourself the question you think he would ask you, i.e. why is it important for you to know his location ahead of the session. What would you gain by knowing? Is it that you would just feel more comfortable; that you want to know a bit more about the objects in the room; that him being in a very personal space which he is sharing with you make you feel closer in some way to him?
I don't see any reason why you shouldn't be able to ask him the question, but be prepared if he does come back with 'why do you want to know?'
It could end up being a good topic for disucssion and go in ways you might not expect...