Why Is ‘Elohim’ Grammatically Plural?

If G-d is one, why does the Hebrew name Elohim take a plural grammatical form?

Elohim is technically plural, but unfortunately the lack of knowledge of Biblical Hebrew can make a simple question sound difficult to the outsider. In Hebrew, as in ancient Arabic and Latin, respect is conveyed by using the plural (“Pluralis majestatis”), sort of like the “Royal ‘we’” in English, where the king refers to himself as “we”. See for example Isaiah 19, 4 where the Bible uses singular and plural together regarding the Egyptian king: “… in the hand of hard (singular) masters (plural) and a brazen king”, where obviously that monarch is the one and only ruler. Similarly in Breishit 39, 40 regarding Potiphar, “And Joseph’s masters (plural) took (singular) him”; and (42, 30), regarding Joseph, “that man (singular), the masters (plural) of the land”; Shemot 22, 10, “its owners (plural) shall accept (singular) it”; and (21, 4) “if his masters will give (singular) him a wife”. None of these could have ever been misconstrued as referring to several people, although they are all technically plural! The term Eloha, which is without that respectful plural, is almost never used in the Torah and only in a poetic form (e.g. Dvarim 32).