While Ljossalfheim is widely accepted as one of the nine worlds among scholars as well as practicing heathens the information we have about this realm are actually very sparse and its inhabitants, the Ljossalfar or Light-Elves, do not appear in an active role in the sources at all. While Dwarves, Giants and Gods are very present in the sources, there isn’t a single story about an Elf nor about a human interacting with one.
In the sources it is said that Ljossalfheim was given to Frey when he was still very young (Grimnismal 5). A closer look at the corresponding Stanza reveals though, that what is given to Frey isn’t Ljossalfheim but Alfheim. In Gylfaginning Snorri talks about Alfheim as well, calling it the home of the Light-Elves and stating that the Svartalfar dwell in another realm entirely, located beneath the earth.
Nothing more can be gleaned from the Edda’s, yet we know from many references there, that the Norse Cosmos definitely consisted of nine worlds. Ljossalfheim works well in a magical context but is the one world in the Norse Myths with the most tenuous roots in the sources.