I cannot say. Which Calvinist are you talking about? You will have to specify precisely what you mean by "predestination" and "election".
If it helps, God knows all things in His Eternity. Time is a part of His Creation, so that, what for us His creatures is the end of time, is a present reality to God. He already Knows those who are "saved" and who, if any, are not. From our perspective, we all still need to freely choose to persevere constantly in His Grace to be saved.
We are all condemned to Hell except for the Sacrifice of Christ. God Wills that all men be saved and offers His Grace, through the Infinite merits of Christ's most Holy Passion, to all so that they indeed may be saved. Other than that, all I can say is that no one need be lost for all eternity. We should all hope, per Christ's command to Love, that Hell will be empty at the end of time. Anybody who freely rejects God's Grace is a fool indeed!