Most Helpful Guy
Have a reason to go to lunch, then ask him to do lunch over it. For example if you need help with something, ask if he'd like to get lunch so you can talk about it over food. Food is the best thing to get people together, talking
Most Helpful Girl
if it was me i would just start some small talk then ask what his doing on the weekend or whenever u wanna go for that lunch thing and if he says nothing just go for it and say wanna hang out, we can go for lunch or something?