Prevevient Grace is a better concept than irresistible Grace although not altogether accurate.
I really haven't put together my thoughts on this completely yet, but I will try to explain what I mean.
Upon hearing the Gospel of truth the Holy Spirit begins a work of conviction that weighs against the will of the human. (The human will only serves to resist the gospel and God) some will muster up resistance and reinforce their resistance, but others their will breaks and they submit, and grace enters in by the word of the gospel (thus some plant, some water, and some harvest) and convinces of Jesus and this human who has under the weight of conviction is broken and now convinced, repents and believes. Now this person is regenerate and becomes joined to Christ in baptism sealing them in Christ's death burial and resurrection by the Holy Ghost.
But the man who rejects hardens his heart and becomes bitter in his conviction, reinforcing his rejection and unless his will be broken he will die in it and be damned.
This is how I see it from the Bible.
I don't see irresistible Grace at all, I do see many reject grace, and many broken under the weight of conviction, or as scripture describes as cut through the heart.