Let us look at this verse:
"According as he hath chosen us in him before the foundation of the world, that we should be holy and without blame before him in love" (Eph.1:4).
Once a person is "in Him" or "in Christ" he is saved:
"Therefore I endure all things for the elect's sakes, that they may also obtain the salvation which is in Christ Jesus with eternal glory" (2 Tim.2:10).
So we can see that being chosen before the foundation of the world is in regard to salvation since the elect are chosen "in Him." In other words, no one can be chosen "in Him" unless salvation is first secured.
And since the "other sheep" are already His sheep before they even hear the voice of the Lord then I cannot see that it is possible that Ephesians 1:4 answers anything about this subject.
"I have (present tense) other sheep that are not of this sheep pen. I must bring them also. They too will listen (future tense) to my voice, and there shall be one flock and one shepherd" (Jn.10:16).
Come off it, how can the salvation which happens today precede the election [being chosen in Him] before the world began?
Paul says those whom God foreknew He also elected [chose] you are saying that He didn't know. How can He plan, predestine YOU to be saved if He did not foreknow you?
It all begins with foreknowledge.
The most precious doctrine in the bible beside salvation. God knew ME, He chose me, He planned my life...how can it fail? He has loved ME from everlasting to everlasting.
Hallelujah, no wonder I love Him.