Since this is the beginners forum, I'm going to make an assumption that the OP is unfamiliar with the concept of the snap roll. What plane are you flying? "Popping" the elevator as you describe it, depending on the plane, can change the angle of attack of the wing abruptly, puting the wing tip into a stall. This is the normal way to initiate a snap roll, and that might be exactly what you're seeing. In which case the answer is to use less elevator to bring the nose to vertical. Your plane may be doing exactly what you're telling it to do.

Brad