Let me say right off the start here that I do not proffess to have the answer to this question, however I have some musings as to what this may be all about.
Let's say God is standing outside of time looking at the whole of creation, from the beggining to the end, and let's make creation a fruit tree of some kind.
He will harvest (or elect) the fruit from the tree, which was of course the reason for planting the tree in the first place (predetimernied). He will also cut away the dead and fruitless branches and discard them so that the tree will have only healthy fruit bearing branches for the next season.
Now this analogy is definately flawed, in that the branch of a tree does not choose wheter or not it will produce fruit, or die.
We are like a branch that has the choice whether or not we will allow the gardener to prune and cultivate us (free will). We have been given the choice to be a fruitfull branch or not.
Now I know that this analogy is flawed, and very possibly the concept as well but it is the concept I'm getting at. Please don't get lost in attacking the analogy. I hope what I am getting at is clear enough as I have lost half the ideas I had when I started to type this post. The mind is faster than the fingers.
------------------
Saved by an incredible Grace.