@Linkat,
I will like to recommend searching an evaluation with a physical medicine specialist. Artritis is rear to be so specific on an elbow. Usualy hands or any of the weight bearing joints are the ones affected.
I concur with Bfly on the bursistis possibility, also a tendinitis, an epitrocleitis, a local myositis and osteoartrosis are other options. Better make an appointment even if does not seems like a life treathening complaint it is altering your quality of life.