What we call the beginning is often the end. And to make an end is to make a beginning. The end is where we start from.
Eliot is speaking of narrative, of course, the interpretation of which is closely tied to the way the story ends. We are launched into a story at its beginning (or what is presented to us as the beginning), but the lens through which we understand the story is the note on which it concludes. We are entranced by beginnings; we judge by endings.
Good writers and good editors know this. They know all about making a story compelling, the writing engaging. And that's what helps draw audiences.