Read a certain way there is a contradiction; but more likely you have a misunderstanding.
First off, one should define Free Will as there are several definitions and that may be the root of the problem.
@Arial can explain herself best ... but as I understand her ....
The will is free to do what it desires most (this is Augustine's definition and probably best represents the definition of Calvinism and it's my definition)
The will is NOT free to choose its desires according to Calvinists. Arminians, at least when it comes to a decision to believe salvificly or not, disagree; they believe people can choose their desires in this situation.
I think that's where the seeming contradiction is explained. Again, Calvinists contend that we have free will to follow our desires which is a free choice, but we do not have free will to choose our desires. According to Calvinists, no one desires to believe in Christ until they are regenerated by the Spirit which 100% of the time causes a person's desires to be change such that they now desire to believe and in fact always follow this desire and believe.
Again, the will cannot choose what it wills (desires). That is circular logic. God determines all our desires.
Aside: I don't think you've acted as a troll in the many post I've read by you ... I think you've conducted yourself well. (that being said, I may have missed something ... giggle)