[WingedDog]

I never had ingame situation when I needed to build my tactic around standard-bearers, so I'm not 100% sure, but logic tells me morale starts to fade when units leave area of effect of standard.

I can give you some other advices to keep your elephants on the battlefield longer:
- if you have priests lvl 2 make them cast Sermon of courage on elephants;
- larger the squad - harder to make it rout. Dont send your elephants on the battlefield by squads of 1 - gather them in big group(s);
- cast low level protective spells on elephants: body ethereal, luck, mossbody, protection, etc.