JC - Chapter 2

James E. Talmage states -

"We affirm, on the authority of Holy Scripture, that the Being who is known among men as Jesus of Nazareth, and by all who acknowledge His Godhood as Jesus the Christ, existed with the Father prior to birth in the flesh; and that in the preexistent state He was chosen and ordained to be the one and only Savior and Redeemer of the human race. Foreordination implies and comprises preexistence as an essential condition; therefore scriptures bearing upon the one are germane to the other..."

He then proceeds to provide such scriptural evidence.  I will mention a few -

"...behold, my Beloved Son, which was my Beloved and Chosen from the beginning..."  (Pearl of Great Price | Moses 4:2)

"IN the beginning was the Word, and the Word was with God, and the Word was God.
2 The same was in the beginning with God.
3 All things were made by him; and without him was not any thing made that was made."  (New Testament | John 1:1 - 3)

"And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth."  (New Testament | John 1:14)

"But with the precious blood of Christ, as of a lamb without blemish and without spot:
20 Who verily was foreordained before the foundation of the world, but was manifest in these last times for you..."  (New Testament | 1 Peter 1:19 - 20)

"Who hath saved us, and called us with an holy calling, not according to our works, but according to his own purpose and grace, which was given us in Christ Jesus before the world began..."  (New Testament | 2 Timothy 1:9)

For I came down from heaven, not to do mine own will, but the will of him that sent me."  (New Testament | John 6:38)

"I am the living bread which came down from heaven..."  (New Testament | John 6:51)

"What and if ye shall see the Son of man ascend up where he was before?"  (New Testament | John 6:62)

"...O Father, glorify thou me with thine own self with the glory which I had with thee before the world was."  (New Testament | John 17:5)

And there is much more.  There is much more evidence that we also were with God in a pre-mortal existence.