That list of TCs and qlvls is only for uniques. Don't worry about it if you are after socketable items.
ilvl (item level) is a number that describes where you get an item from. If it is dropped by a monster, the ilvl will be equal to the mlvl of the monster that drops it. The mlvl of a monster is equal to the level of the area you it in, unless the monster is a boss or boss minion (gets a +3 bonus) or a champion (+2).
Because elite items tend to be dropped only from late NM onwards, they will typically have ilvls well upwards of 50.
Now, the socket quest always gives you max sockets for an item. However, max sockets depends on the ilvl of the item as well as the type of item it is. Most sites though only list the highest max socket value (there are usually three), which applies to items of ilvl 41+. Unfortunately for what you want, socketable elite items will pretty much always be ilvl 41+, so they will always have the highest max socket value and get that many sockets from Larzuk.
As for which elite items can drop where, that is not simple to answer. Base items depend on TCs, not monster levels. The earliest elites are TC60, but most of the elites people care about (ie not Truncheons or Giant Conches) are up in the TC75+ area. The highest TC that a monster can drop slowly increases as you go through the game, but I am not going to list every item type and where it can drop here. If you want to be more specific maybe I can help.