Does it differ from what you said here?
There is really no foreknowledge with God because He lives in the ever present "now."
God, being both infinite and eternal, is not bound by either space or time, as we are. This principle has long been understood within Calvinist circles. William Ames (1576-1655) was one of the foremost of Reformed thinkers, often known as "the Learned Doctor Ames" because of his great intellectual stature among Puritans, said the following:
"There is properly only one act of the will in God because in Him all things are simultaneous and there is nothing before or after. So there is only decree about the end and means, but for the manner of understanding we say that, so far as intention is concerned, God wills the end before the means" [emphasis mine](William Ames, The Marrow of Theology, translation and introduction by John, Dystra, Eudsen, [Boston: The Pilgrim Press, 1968], 153-154).
According to Ames all things in the eternal state are "simultaneous and there is nothing before or after." This idea that all things are "simultaneous" with God was expressed by another prominent Calvinist author, Loraine Boettner:
"Much of the difficulty in regard to the doctrine of Predestination is due to the finite character of our mind, which can grasp only a few details at a time, and which understands only a part of the relations between these. We are creatures of time, and often fail to take into consideration the fact that God is not limited as we are. That which appears to us as 'past,' 'present,' and 'future,' is all 'present' to His mind. It is an eternal 'now'...Just as He sees at one glance a road leading from New York to San Francisco, while we see only a small portion of it as we pass over it, so He sees all events in history, past, present, and future at one glance" (Loraine Boettner, The Reformed Doctrine of Predestination [Michigan: Wm. B. Eerdmans Publishing Company, 1932]).
The LORD sees all the events in history with one glance. So any passages which speak of His foreknowledge is not to be taken literally.
And so with the LORD it is true that the moment when someone believes is with Him also the same moment which can be said to be before the world began. But no one is saved in "time" until he believes. And the following verse is using figurative language and from what is said we can know that no one is chosen until they believe:
"But we are bound to give thanks alway to God for you, brethren beloved of the Lord, because God hath from the beginning chosen you to salvation through sanctification of the Spirit and belief of the truth" (1 Thess.2:13).
