I have an iPhone 5s, iPad mini retina, and just got a 2013 macbook. Handoff has been working fine between the iPad and iPhone 5s. If an app is running on one, a small icon appears in the lock screen of the other. But on the macbook, the current shared app is not shown on the iPhone's lock screen. Surprising because what is on the iPhone does show in Yosemite. I also can send a map or contact to the iPhone through the send to button. Do the apps you have going in Yosemite not show on the iOS lock screens? Like other iOS devices do?