mac book air 11 mid-2012 does not work with Dell U2410

I just bought a new 11" MB Air - mid 2012. Love the laptop, but didn't want to spend 1000 bucks on the Cinema Display external monitor. I had read that the Dell U2410 supports Display Port, so happily ordered it based on glowing reviews about the display quality and the vaunted backward compaibility betwen Thunderbolt and DP. I also ordered a vanilla mini-DP to DP cable as well as a Belkin mini-DP to HDMI adapter, figuring I'd be covered just in case the DisplayPort approach went pear shaped.

I just unboxed the Dell U2410 and tried both cables, but the monitor does not even recognize that the MB Air is connected to it. Nothing I do seems to work. It seems like everyone is reommending I go get a Thunderbolot-to-DVI adaptor. Will give that a try next and let you know how it works.