Lor Spakewheeled woke up as usual,
“…woke up as usual…” needs to be rephrased. As it is it suggests as an alternative that he might not wake up, which seems weird. Would be more accurate to say that he … “woke up in the usual way…”. That is to say, as phrased, the fact that he woke up is emphasized, when it looks like you want to emphasize that he awoke in the routine to which he was accustomed.
the smooth stone floor chilly on his feet,
I’d add a line that mentions that he swung his feet off the bed, or change “woke up” in the previous part to “got up” or “got out of bed”. The phrase “woke up” only tells us that this person (well, dwarf) is no longer asleep: a person can wake up without getting up.
his fingers slipping into the familiar grain of the mahogany bed frame.
Do you mean his hands were between the bed frame and mattress? I wasn’t 100% certain on this.
One of the finest beds made. ‘Grown, not made’ he remembered, for the umpteenth time since he’d won it from an elf. An elf could never hope to hold his liquor against a dwarf, especially not so heavy a drinker as Lor.
Add “in a drinking contest” to the end of the second line. It’s not too tough a stretch for a reader to understand that the bed was won in that way, but the transition between the second and third lines (and thereby, those two thoughts) is really rough.
You have an opportunity here to really flesh out your character. Give us a little more detail on Lor’s memory of how he won the bed. It doesn’t have to be long, just a flashback of two or three sentences that give us his impressions of the event.
For the first time, however, he found an envelope snugly fit between the granite floor and the block of obsidian-on-hinges that was his door. It bore the royal insignia, the oh-so familiar diamond with an axe carved into each and every facet.
“For the first time, however…” almost feels like a response to the previous line about the drinking contest, as if it's about to be suggsted that maybe an elf
did win one. It’s far enough removed from the opening statement that Lor woke up “as usual” that the connection between that opening and this sentence is very weak. Maybe find a different way to suggest that this is unusual.
I’d suggest a little action on Lor’s part: something simple such as getting out of bed and going to examine the letter. Just to have a slightly better frame of reference for your readers.
Curiously enough, it bore also the name of his sister. His sister that should be dead by now. No dwarf survived in the mountains after being exiled. He dropped it onto his bed and grabbed his cap. No time for letter reading when the mining corps had found a new coal vein.
Lor’s attitude towards his sister seems pretty cold if he can’t be bothered to read the letter, particularly if she might be dead or dying, why would this be? What is so harsh about the mountains? Note, too, that you’ve painted Lor as being curious about the letter; it seems odd that he wouldn’t at least glance at it.
I plan on going over this story one piece at a time, maybe one a day. If any of those questions are addressed in further pieces than please disregard.
Thus far my advice is twofold
1: Focus on clarifying action. The scene feels a little disjointed because it's not always 100% certain just what is going on. A lot of this has to do with #2.
2: Word choice. Make sure that the words you use express the actions and details of the story as clearly and directly as possible. The "woke up" vs "got up" bit is an exampel of this. Really consider what each word and phrase means, and use the one that seems to carry the meaning closest to the one you want.