Lars, viiielen herzlichen Dank! Many thanks! That did the trick! I have added {{blog>?20&nodate&nouser}} and the entries have disappeared.
Now I just need to hide the horizontal rule. ;-)
Okay, I managed to erase it.
1. Create a userstyle.css in /dokuwiki/conf/
2. In order to erase the line from within the blog-plugin, add
.level1 {border:0 !important;}
BTW if you want to hide / erase the line below the title of your entries, add
h1 { border:0 !important;}