Sorry, buddy, I didn't know where you were with C2 yet. :)
You have many different options to record the character's Y-position on the screen. You can use a global variable, setting it to the character's Y-position when they contact the edge or whatever causes them to wrap. When it happens, set the character's Y position to that variable and their X position to where they should emerge.
You could also instance variables, which would accomplish the same thing but prevent the variable from being manipulated by other parts of your game.
The manual has more details on how to use variables, but it looks like that might be a viable option.