Our experience with wisteria is that you can cut it back—almost to the ground, in fact—and it will return. If yours is happy (that is, thriving where it is), it should return as well no matter when you cut it. With no detail about your arbor, we offer this: Can you introduce supports to your arbor? Increase its size or strength without cutting the plant? If you cut the plant, perhaps you don't need to cut it to the ground, but can remove only a portion. Be aware that you will get (maybe you already have) new plants sprouting at the base, no matter what you do. We hope this helps!