XPath to select nodes whose name starts with

I have XML that looks like this:

<detail>
  <address>
    <line1/>
    <line2/>
    <line3/>
    <postcode/>
  </address>
</detail/>

There could be any number of <line*> nodes which I want to select, and other nodes which I don't want to select.

I have tried this, which doesn't seem to work (in C# anyway):

/detail/address/[substring(name(),4) = 'line']

Al, help appreciated!