Hi Marc

On the Outlining toolbar, look for a button with alternating black and grey
lines. Its tooltip is Show First Line Only. That button (or its shortcut,
Alt- Shift-L) toggles between showing all a paragraph and the first line
only of a paragraph.

For further information, see
How to save yourself hours by using Outline View properly
http://www.word.mvps.org/FAQs/Formatting/UsingOLView.htm

Hope this helps.

Shauna Kelly.  Microsoft MVP.
http://www.shaunakelly.com/word