We're all presuming that both words are a preterite for the verb "light". This may be a personal idiosyncracy, but I feel there is a difference between "light" meaning illumine, illuminate and meaning kindle, set fire to. To me, 'lighted' goes with the former, 'lit' with the latter. I would never say, "She lighted the fire before dark." But I would say, "The fire lit up the room enough to read by," which contradicts what I just finished saying, so it's not hard and fast. I would say, "He lit the lamp and lighted up the room." (Lighting a lamp, even an electric one, is the same as setting fire to a candle- or lampwick, as any orthodox Jew could tell you.)