When in writing would "telling" be better than "showing"?

You "tell" when you're "zooming out" of the story frame to give a wide-sweeping account of what's happening. You "show" when you "zoom in" on a particular scene.

Example: You tell when a lot of time passes between the last scene and the next, you tell backstory (unless you show it through flashback), you tell in your prose in between dialogue to inform the reader of something that was otherwise unknown through just the dialogue. You tell when you're giving a summation of information (a.k.a. a quick description of appearance, setting, etc).

Tolkien isn't exactly the best author to look to for writing mechanics. He wrote during an era when "telling" overshadowed "showing." It was a popular writing style at the time and has since grown obsolete. The telling in the beginning, though, is "backstory" so as to set a sense of place in the reader's mind. He does the same in LOTR.

Usually authors introduce a story or a scenario by 'telling' about it's happenings.

BUT

Most of the times, They get you acquainted with the set up by a combination of telling some parts and showing the others. So it's the combination of both that actually works best.

You could use your skills to get a reader hooked on by your 'telling' skills, and then you would get them the thrills by 'showing' them.

So, it's best if you tell and show them what you mean. Get them in by telling and then let them experience by showing it :)

Hope i've helped :)

Best of luck with your book

I would say, if you are giving a quick summary of something that happened in the past, you can tell rather than show. This is useful if it is only important that the event happened and not necessarily all of the details about the event. IMHO

Telling is best when there isn't a scene happening. Telling is great for transitions, introductions and things that don't require an entire scene to describe.