Another option is to simply have the NPC disabled at the start of the game and not worry about the journal entry.
There is a script called "statrup" that exists as a run once script that says to put run once items in it, like disable NPCs. However, experinced modders seem to object to this use of the script, so to keep everyone happy, there is a simple script you can make that will handle it:
Begin DisableNPCscriptshort DoOnceif ( MenuMode == 1 ) ReturnendIfIf ( DoOnce >= 1 ) ReturnendIfIf ( DoOnce == 0 ) "YourNPCName"->disable set DoOnce to 1 stopscript DisableNPCScriptendIfEnd DisableNPCScript
Save this script in your script editor (you will need to comment out the stopscript, save, then uncomment the stopscript and save again) and add the script to your startup scripts in the CS under gameplay > edit start scripts.
If you do it this way, you can choose from a variety of ways to enable the NPC later on, either with another script based on journal or an onActivate kind of thing, or dialgue.
The main difference between this script and the one offered by iwasavampireonce is that you can add many more objects and NPCs to this script if you find you need to, and it will only run once, whereas the journal based script will run that script constantly until the conditions are met.
Also, get Morrowind Scripting for Dummies version 9. It's really helpful, believe me, you won;t regeret it if you are going to do any scripting at all.