If you only have a PS CC subscription then that does not cover other applications available as CC products. If you want PS and LR there is a special Photography Plan that you might prefer over the price of PS alone.
Creative Cloud Plans
Chat support - For the link below click the Still Need Help? option in the blue area at the bottom and choose the chat option...
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Creative Cloud support (all Creative Cloud customer service issues)
http://helpx.adobe.com/x-productkb/global/service-ccm.html ( http://adobe.ly/19llvMN )
OK thanks - but how can I swap to this plan without having to cancel my current PS CC plan as I have various PS plugins installed - is there any way to upgrade automatically
many thanks for a prompt response
You should contact Adobe Support to see what they can help arrange. It could be as simple as signing out and back in again between the changes in your subscriptions... or even simpler where you do no more than download LR and start working with it as part of the Photography Plan
cheers I'll drop them a message