Pudding and loo are quite probably no more "English" in origin than dessert and toilet, and whilst pudding is an old word (though its meaning has changed) loo is very modern...
Arguing that dessert and toilet are pretentious because they are from French is totally hypocritical, given the fact pudding and loo quite likely are also from French...
pudding
"c. 1300, "a kind of sausage: the stomach or one of the entrails of a pig, sheep, etc., stuffed with minced meat, suet, seasoning, boiled and kept till needed," perhaps from a West Germanic stem *pud- "to swell" (cognates: Old English puduc "a wen," Westphalian dialect puddek "lump, pudding," Low German pudde-wurst "black pudding," English dialectal pod "belly;" also see pudgy).
Other possibility is the traditional one that it is from Old French boudin "sausage," from Vulgar Latin *botellinus, from Latin botellus "sausage" (change of French b- to English p- presents difficulties, but compare purse (n.)). The modern sense had emerged by 1670, from extension to other foods boiled or steamed in a bag or sack (16c.). German pudding, French pouding, Swedish pudding, Irish putog are from English. Pudding-pie attested from 1590s."
loo "loo (n.1)
"lavatory," 1940, but perhaps 1922, probably from French lieux d'aisances , "lavatory," literally "place of ease," picked up by British servicemen in France during World War I. Or possibly a pun on Waterloo, based on water closet."