Jon
There are five notations like the two you've mentioned and they are to be found on page 331 of Gordon's 'An Introduction to Old Norse'
Here they are
 
e - n    (einhvern) = accusative of the person
e - t     (eitthvat)    = accusative of the thing
e - m   (einhverjum) = dative of the person
e - u    (einhverju)    = dative of the thing 
e - s    (einhvers)     = genitive of the person or thing. 
 
As for your example, hlotnast (ađ), v. refl. to fall to one's lot (e-m hlotnast e-t) - very crudely I would transcribe this as 'It fell to the lot for him(e -m) with death(e -u). Properly translated we might say 'It was his lot to meet death. Hope this helps
Cheers
Jed