Some folks using 'elm' as their mailing program, and seeing a lot of
header-lines, may be making the same mistake I used to make: I thought
that the original sender's address was being stripped off somewhere along
the line.
 
Not so.  There are *more* header-lines!  Hitting the h key (for header)
reveals them, and among them is the address of the original sender.  It's
high enough on the screen so that if your reply command splits the screen
while you enter the address, you can still see the header-line with the
senders' address.
 
Hope this helps.
 
--bayla