Assume God is infinite, and also that God is at the beginning and the end of the universe.

By infinity, God's power-level is so big that we can't comprehend it, however, this universe is a product of God, and we can use its components to comprehend levels beyond our grasp.
By beginning or end, we get omniscience we get presence in more than one place. If we gather based on our current understanding of time that God is omniscient by virtue that he can occupy more than one location at once, his origins are rendered inconsequential as he is not constrained by a singular sequence of consequence.