Yes, strike is available. The best way to apply the Strike effect is by creating a Character Style.
Assuming you are using LO 4.2.4, just
1) Display the sidebar (menu View >Sidebar)
2) Select some words you want to strike, and click on the Strikethrough button (4th under the Font name)
3) Click on the Styles and Formatting button (2nd colour icon from the top on the right edge of the LibreOffice window)
4) Click on the small "a" icon (Character Styles) just under the Sidebar title "Styles and Formatting)
5) Click on the 7th icon (last) in the same row as the "a" icon (New Style from Selection)
6) From the menu, choose New Style form Selection
7) Name it Strike or whatever you prefer
From now on, to strike any word or words just select them and double click on the Strike word showing in the list.
This sounds a bit complicated (of course you can just do steps 1 and 2...) but this is the most consistent way to format text. Advantages? If you later decide that you want all words that you have already stricken with a double line or crosses, you just need to Modify the Strike style.
@AnthonyH Please mark the answer that worked for you as 'correct', so it is clear to other the question was solved. Thanks!