Let's clear a few things out.
In CoronaLight, you include or exclude objects for the illumination.
You specify which objects the light affects, nothing about the visibility of the light.
The light visibility is controlled separately, for specific ray types.
If you want to see the light source through an object (either affecting it or not), the material of the object should be set up accordingly.
There is no way of setting up an object to be invisible to another - this can be done only for specific view/camera.