Firstly, elephants have really thick hides (it takes a special calibre of rifle to get through, for instance), so they don't really require any barding - that would only weigh them down and/or make them uncomfortably hot. Now, having forgone the weight of the armour, the owner is in a position to mount a houdah atop the elephant, and man it with a couple of spearmen/archers. It is not uncommon to have some tapestries hanging from the sides, and these DO in fact serve to enhance the hapless pachyderm's dermal toughness... Elephants do have a weak point that could could be exploited, though: their limbs can be attacked with axes should aggressors get past the arrows and the spears, so maybe some light armour around there is indicated. There you go, elephant adequately protected from some distance, and right down to close range.
/end_frivolity
PS: Oh, and keep the poor creature the hell away from T.A. Edison!
