@RoyB, I would encourage you to think of noter/drone play not as a beginner "stage" in your dulcimer playing but as a unique style that may be relatively easy to learn at first but still requires years of practice to master. You might consider embracing that style and planning on developing your noter technique over time.
On the other hand, if you want to play more modern styles of music on your dulcimer, you might be able to despite your arthritis. With five fingers and only three strings, there are multiple ways of fingering chords and playing melodies across those strings. I have a private student who has pretty bad arthritis in 1-2 fingers of her fretting hand, and we find ways to work around that limitation, either by finding alternative fingerings or sometimes revising arrangements.
And I should add that there are some great dulcimer players who don't use their pinky at all.
My advice is to concentrate on learning the instrument and playing the music you like. Unless your arthritis gets much, much worse, there will be work-arounds for any obstacles you encounter.
Dusty T., Northern California
As a musician, you have to keep one foot back in the past and one foot forward into the future.
-- Dizzy Gillespie