Really you shouldn’t need lxde just to configure wifi. If I were you i would probably just reimage your SD with a fresh install and follow this video to set up your WiFi:

I don’t know too much about how lxde affects the boot sequence. You could always try going into the set up script and re-enabling emulationstation to start on boot but its probably easiest to just reimage without using lxde (it takes up a fair amount of space on the pi).