How to: Split a arc (or line) using another?

Hello,
I have a very basic question about bisecting arcs / lines. How can one (in Salome_6.3.1, or older versions) cut in two an arc (or line) using another arc (or line)? I tried Partition and it does not seem to work. I have attached a screenshot where I want to "trim" the arc using the red vertical lines, and subsequently "trim" the two vertical lines using the "trimmed arc". In other words I want to get rid of the "extra" length of the arc (shrink the 'smile') and the bottom extension of the 2 vertical lines. For example: AutoCad has a "trim" feature for doing this. How do I do the same in Salome? Thanks.
Regards, JMB
Hello all,
I am answering my own question! I discovered that Partition DOES work. I just needed to explode the partition into its component edges!
Regards, JMB