God's election is not based on what man will do but instead what God has done. He doesn't say "Oh good, these are the people who will believe in me so I will elect them" - that makes man the master of his election and it is wholly not supported by Scripture.
If God desires to choose those that believe, that is his doing. This is also shown in the story of Gideon.
Jud 7:4 And the LORD said unto Gideon, The people are yet too many; bring them down unto the water,
and I will try them for thee there: and it shall be, that of whom I say unto thee, This shall go with thee, the same shall go with thee; and of whomsoever I say unto thee, This shall not go with thee, the same shall not go.
5 So he brought down the people unto the water: and the LORD said unto Gideon, Every one that lappeth of the water with his tongue, as a dog lappeth, him shalt thou set by himself; likewise every one that boweth down upon his knees to drink.
6 And the number of them that lapped, putting their hand to their mouth, were three hundred men: but all the rest of the people bowed down upon their knees to drink water.
7 And the LORD said unto Gideon, By the three hundred men that lapped will I save you, and deliver the Midianites into thine hand: and let all the other people go every man unto his place.
God told Gideon to bring his ten thousand men down to a body of water where they would be tried. God told Gideon to set apart those who lapped water like a dog from those who bowed down to drink. God already knew who and how many would lap like a dog, but he did not cause them to drink in this manner.
But it was God who established the criteria of who would be chosen. A man simply drank water as he did, but God chose those who put their hands to their mouth and lapped like a dog.
And even further, it is directly said that God did this to demonstrate he was the one who saved Israel.
Jud 7:2 And the LORD said unto Gideon, The people that are with thee are too many for me to give the Midianites into their hands,
lest Israel vaunt themselves against me, saying, Mine own hand hath saved me.
So, God choosing these three hundred men because they lapped like a dog does not mean they saved Israel, God saved Israel.
If before the foundation of the world God decided to choose those who would believe on Jesus in time, then God determined who would be saved, just as he determined beforehand those that would lap like a dog would fight with Gideon.
This story is a figure of election if you will receive it.