It is my understanding that carbonation releses CO2 into the system contributing to an acidic state which would be at odds with one of the main working functions of lemon which is to alkilinize the system.
For varieties sakes folks will switch back a forth between lemons and limes or mix then together. Another popular trick is to make lemonade slushies in the blender using the lemonade and ice or even freezing some of the lemonade into ice cubes and sucking on them. You can also try it warm. Notice I say warm if you heat it too much you will destroy the live enzymes in the lemons.
Having just finished my last MC mid Dec and the weather being fairly cool the warm lemonade was a very welcome treat.