Controlling noun prefix

Can someone please point me towards the documentataion that explains how to control noun prefixes.

For example I have the following, but the output describes the Elves as AN Elves, I want it to say SOME Elves.

The idle Elves are people. The printed name of The idle Elves is “Elves”.

The idle Elves are in The Workshop.

The busy Elves are people. The printed name of The busy Elves is “Elves”.

The busy Elves are nowhere.

The output:

The Elves Workshop

You are in the Elves Workshop, there are row upon row of workbenches with toys, decorations and christmas paraphernalia of every type in various states of completion.

You can see a Poster and an Elves here.

See §3.18 of Writing with Inform, “Articles and Proper Names.”

In many cases, including this one, it’s as simple as using the indefinite article rather than the definite the first time you declare it:

Some idle Elves are people.

You can also specify the indefinite article by hand, if that helps:

A vicar is a person. The indefinite article of the vicar is "your local".

You can also use that last trick to make the indefinite article of a singular noun “some,” so you get “Some water is here” whenever that is required. But in this case, Inform will use the fact that you defined the Elves with “some” to conclude that it ought to say “Some Elves are here,” and that’s what you’ll want to happen, so no special treatment is required.

Perfect. Thank you!