He is in the clouds In dreamland, entertaining visionary notions; having no distinct idea about the matter in question.
To blow a cloud is to smoke a cigar or pipe.
A dark spot on the forehead of a horse between the eyes. A white spot is called a star, and an elongated star is a blaze. (See Blaze)
“Agrippa He [Antony] has a cloud on his face.”
(St.). Patron saint of nailsmiths, by a play upon the French word clou, a nail.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894