Spanish word cuando comes from Latin quam, and later Latin quando ((interrogative) "When?". (relative) "When". Because. When.)
quam (Latin)
(after comparative nouns) than. (in comparisons) as. In what (which) way, to what (which) degree; how, how much, as much as, as far as.
quando (Latin)
(interrogative) "When?". (relative) "When". Because. When.
cuando (Spanish)
When When.