Lithops are one of my favorite cacti/succulent and were one of the first ones I bought.
Lithops require no water during summer months because this is when they are dormant and do not grow. They start growing a little bit in the fall months and then really take off in the winter months, slowing down in the spring and then back to summer.
The only time I truly water mine is a lite misting in the end of September and then water once in November.
Because they are winter growers they require a decent amount of light to really be kept looking natural and healthy.
I am personally having to bring some 100 cacti and other tropical plants inside this winter because of the zone I live in. they will go in my front window that gets a good amount of sunlight, they will also have two hanging fluorescent light hoods that each hold 4 of the large bulbs. but im keeping a huge collection.
If you really want to help your little guy go, give him a lamp, the more light the better normally when it comes to artificial lights. I like the CFL(compact fluorescent light) bulbs because of their low power consumption and broad range of UV light they produce.
If we are who we are, and who we are is changing from added experience from moment to moment, then who are we?