Which mosques are we talking about here ? If your talking about mosques in the Middle East or South Asia then YES, domes and arches are the norm. read more
The arch is an ancient IRAQI technique to build a bigger room-without central pillars—and thus a bigger Mosque is available , for a bigger community. The dome, also, from an engineering point of view is a good way to build a strong roof, and allow sunlight in, and a high celeing. read more
Arches and domes on a Mosque are architectural designs used to differentiate a Mosque from other buildings. Nothing particular. The Muslims may offer prayer in any building having no arches or domes. read more