What pattern? Daggerfall and Morrowind are the only two that split the word for abbreviation. It's not O-Blivion, it's O-Bliv-I-On. So why don't we abbreviate OB as OBIO? Because the O and the B form the strongest sounds in the title. Same thing with Skyrim. The Sky is more important than the rim, specifically the SK. Daggerfall, Morrowind, Oblivion, Skyrim.
Fair enough. For Daggerfall and Morrowind it made sense to split the abbreviation at the new syllable, seeing as they were ... uh, pretty big (on paper). The syllables, I mean. Gah! You know what? No abbreviation for me, indefinitely.