What is the best flat-earth argument, and how do you respond to it?

First, the threshold question I put to any flat-earther is: do you believe in satellites and that they take real pictures? If yes, I will debate; if no, he is in a cult and I want nothing to do with him, because most flat-earthers think NASA is a big conspiracy and satellites are all holograms, and that is game over, because you are not dealing with reality. Weather satellites 22,240 miles up at the equator can see the whole earth at once; satellites only 300 to 500 miles up cannot get a panoramic view, so they get peels, or strips, of the earth and piece them together back in the laboratory, which the flat-earthers dishonestly call faking. Their best argument is Lake Michigan: from the Michigan shore you can sometimes see the Chicago skyline about 60 miles across, and they say that if the earth were curved the skyline should be about 900 feet below the horizon, so the earth must be flat. But it is a fact of science that in April and May the temperature difference between the cold water and the warm air is at its greatest, and that disparity bends the light rays, the same way a straw looks cut in two in a glass of water. The bent light lifts the Chicago skyline into view, and that is why you can only see it in April and May and not in July or December. This is why you have to be very careful with your science, and thank God for science, because it can show that the earth is curved after all.