How do I make an ordinary piece of architecture appear even when the cell is not loaded (LOD)

This piece --> RifRmSmFirstWall01 will be quite extensively used in an exterior environment of mine, and I would like it to be visible from afar.
What is the proceedure to follow to achieve this?

http://www.creationkit.com/Creating_a_Custom_Worldspace_with_LOD

Follow the instructions for "Generating Object LOD."

If I follow that proceedure, will the RifRmSmFirstWall01 appear as a distant object? , As far I know, that object is used in interior cells in the vanilla game.

Oh, if it's an interior piece, than no. You could check "Is Full LOD" for the object, but doing that on too many pieces isn't a good thing (it has the entire, full-detail model loaded all the time). The best route is to simply create a LOD model for the mesh.