This is kind of interesting. Three possible words for "on" have been given: dirce, seldicfle, and cikna. Dirce ("radiating") is probably too specific, since it applies only to light emitters. (I suppose that could include radio transmitters, microwave ovens, and x-ray machines, or even heaters, stoves, and ovens.) Seldicfle ("is a destination for electric current", or "is powered") is useful for any device powered by electricity. Cikna ("awake") is far too metaphorical, since a light-bulb could hardly be said to be awake/alert/concious. Cando ("inactive/not moving") is also troublesome as a way of saying a light-bulb is off, since we normally don't think of light-bulbs as moving no matter whether they are on or off.
Another way of asking this question is "do viska tu'a xu ledo tergu'i pu lenu do cliva", which is a shorter way of writing "do viska lenu xu ledo tergu'i cu co'e kei pu lenu do cliva", "Did you see whether your light was doing something before you left?"
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You should probably be using "le" instead of "lo" in a couple of places. The speaker is probably thinking of a specific light and certainly thinking of a specific event of leaving. Translating your Lojban back to English, I would probably come up with "Have you seen any of your lights on before you've left?".