Welcome, Mryan!
I can't give you any short, pithy quote that will answer your question. In most of Lewis' literary works he goes quite deeply into Virgil's influence on literature. If I understand your question correctly, I think what might help you the most would be his Preface to Paradise Lost, chapter VI, 'Virgil and the Subject of Secondary Epic'. You can find Preface to Paradise Lost in most college libraries, I believe.
Hope this helps.
Selah,
Sven