delay icon visibility

I have a Menu Button on my site header. I also have a horizontal menu on my header. I want my viewers to be able to have access to the menu button as they scroll down the site. Is there any way to make the menu button appear only when the header is no longer in view? I know I can set them item to scroll with page but I only want it visible when the header is no longer visible. It looks kind of strange to have a menu button and a horizontal menu at the same time.