no, it's not illegal, as long as you put lite-c logo and the web adress on yout own startup screen. I mean you are allowed to create your own startup screen this way, you only need to keep the logo and copyrights.

It basically works this way:
you create a windows form with your custom image, and make this form the topmost window(always on top) so when you start your game it covers the ugly white startup window. then you run your game from this form and listen for a special windows message that you will send from your game(lite-c). Then when your game starts, you send the message so that the form knows your game has started and can close down. Then you terminate the form and your game keeps running.