It's not acceptable, Mr. Chairman, and I'd like you to cite the authority you're using in making that ruling.
A member may raise a point of order any time he or she wishes. I quite concur with your ruling that the point of order could be requested after a question has been asked, but the point of order may deal with anticipating an answer that may or may not be appropriate to give; therefore, a member is quite in order to raise a point of order after the question is asked, before the answer is given.
I'd like to hear what your authority is for making that ruling.