Here are the homophones for "an electric flash from clouds" and "make lighter":

An electric flash from clouds:

* Flash (meaning a sudden burst of light, the homophone we are looking for)

* Flesh (meaning the soft part of the body)

Make lighter:

* Lighter (meaning a device used to start a fire, the homophone we are looking for)

* Lighter (meaning less heavy, the comparative form of the adjective "light")

Let me know if you'd like more examples of homophones!