Elst in Friesland, which may or may not be different from Elst in Gelderland

Looking at the maps on Wikipedia, it appears that Friesland and Gelderland are distinct parts of the country with no overlap, so yes, probably not the same Elst.

On the other hand, Google doesn't appear to believe that there is an Elst in Friesland. Do you think the author might have - horrors! - made it up?!