Wrap a single html tag around each block that's generated from a single view
The answer suggested by madhurjya is correct, but I would point out that it is possible to create a template that is applied to all block displays of a certain view. E.g. for a view Blog with Unformatted type of output you can use views-view-unformatted--blog--block.tpl.php to alter all blocks only from that view.

Explore the Theme:Information in the Advanced settings of a view to see all your options.