It doesn't say in the Bible that we should pray for the salvation of lost people. It would be, in effect, asking God to take away their free will so they could accept Christ of their own free will.

You're taking that verse in Acts out of context:

(Acts 26:15-18 NIV) "Then I asked, 'Who are you, Lord?' "'I am Jesus, whom you are persecuting,' the Lord replied. {16} 'Now get up and stand on your feet. I have appeared to you to appoint you as a servant and as a witness of what you have seen of me and what I will show you. {17} I will rescue you from your own people and from the Gentiles. I am sending you to them {18} to open their eyes and turn them from darkness to light, and from the power of Satan to God, so that they may receive forgiveness of sins and a place among those who are sanctified by faith in me.'