You retrieved the scroll from Raghnall, but it was written in Black Speech, which Lorniel is unable to translate.
'I fear we may have been deceived, ${PLAYER}, for this scroll is written in Black Speech and may say nothing of value. I cannot say, for Black Speech is not a tongue with which I am familiar. Even so, I would know what this says.
'Perhaps the Elf Laerdan may have some proficiency in this writing. He is an old friend of my father's and is here in Gath Forthnír.
'Take the scroll to him and ask him his opinion. If it may help us free my father, then we must learn its secrets at once!'
Laerdan is in Gath Forthnír.
Lorniel suggested you seek out an Elf named Laerdan in hopes of learning what Raghnall's scroll would reveal.
Elrond Halfelven is at Rivendell in the Trollshaws.
Laerdan, also unable to translate the scroll, sent you to Rivendell to speak with Elrond Halfelven.