The only effect that has on Reformed evangelism is that of not making false promises to sinners. The command to repent and believe is universal. That only the elect, having been regenerated by the Holy Spirit, will respond and believe is immaterial since nobody knows or claims to know who among those not professing belief are elect and who are not. It's not our job to know, it's our job to fulfill the Great Commission.
If you are lost, according to Calvanism, you cannot make a choice about your decision to be saved, you have to be "called" by God to make that decision.
Essentially you're saying "you cannot choose whether or not you will choose what you are going to choose." That's a philosophical question, not just a Calvinist one :)
All men have a choice when presented the Gospel. They can accept it or reject it. The question is who will choose which and why.
The first problem that Calvanism presents to the person who believes in "free will" is that the scripture obviously shows man with free will. This is clearly shown by what we see with the Adamic fall. Secondly, if there were no "free will" toward service then there would be no reward in service, in that, you serve because you are elected to, not because you freely choose God's purposes and will above that of either the world, the flesh, or the devil.
Calvanism, creates a class of people that they say God has decided should go to hell. They call that an expression of God's love? How about the poor sinner who knows nothing, spends his/her life in agony or misery and then is still forced into eternal damnation because he/she was not among the elect? The argument then that this concept is in line with a "loving God" becomes a fools argument.
It is clear that nothing like this is an expression of the love of God. You will then say to me that the love of God is defined by whatever He does. I will then respond to you that God has already defined His definition of love, and that is found in 1 Cor. 13. What about those attributes speaks of deciding that there are some people you will send to eternal damnation, because they are not the elect, without even a slight chance of exercising the desire to repent???
The scripture tells us that God has given to every man the measure of faith, and that we each (every living human, ie the cosmos) has the ability to be saved if we so desire to obey our creator.
Nothing could be further from the definition that God gives of the attributes of love and mercy in His word than the things that are proposed by the belief in Calvanism. Calvanism is, and has always been a doctrine seeped in error, and has been responsible for many many social ills in this country, europe, and in Africa.
It is time to get rid of it and to move to an understanding of the scripture that is reinforced by the scripture itself.
By the way, you may preach all that you want to but what do you say for your "altar call?" "Whoever is the elect come forward?" "The rest of you sinners can't come forward because you are on the way to hell, and that by the determination of God, not by your own sin or decision to reject the Christ of God."