Middle English asur came from Anglo-French azeure. An older sense of azure is lapis lazuli. Merriam-Webster proposes an earlier Spanish route from Arabic lāzaward and Persian lāzhuward, but marks the Spanish connection as probable.
The probable earlier route is explained, not required in the ordering puzzle.
Sources
- Merriam-Webster: azure
Anglo-French azeure preceded Middle English asur and azure; the proposed earlier Spanish route is probable.
- Online Etymology Dictionary · azure
Meanings of the older forms on the word path.
- Anglo-Norman Dictionary · azur
Meanings of the older forms on the word path.