I guess a lot depends on what you mean by elderly - is 70 elderly?

If someone falls but can get up on their own or with minimal assistance then I would say it is up to them whether or not they want medical attention and if so how to go about getting that help.

On the other hand if someone falls and can't regain their feet then I would call for assistance, irrespective of their age. 

Not sure that age in itself plays a part on when to call an ambulance.