I suggest that you don't know as much about Calvinism as you think.
Actual (non Neo)Calvinists deny the possibility of anything like free will because it reduces the power of God which is total. Now don't tar me with this view- I am no Clavinist. My sister-in-law is an OP Presbyterian and I discuss this from time to time with her preacher. The discussions are amicable and we both see them as sharpening our own respective reasoning.