The CMIP5 models appear to include a 1912 volcanic event, but smaller than the 1904 event which appears to be Mount Lolobau which was a VEI 4. So there is a significant difference between C&U volcanic and the volcanic used for CMIP5. Note that the +0.4 offset I used is about the same as used for CMIP5.
The reason for all this is was there really a Little Ice Age and if so when did it end?
Since I "calibrated" my volcanic forcing to the 1810 to 1840 period which produced the +0.4 offset, I would be of the opinion that a period of cooler than "normal" temperatures due to volcanic forcing wouldn't be over until temperatures returned to the pre-volcanic forcing level. That would be roughly 1930 to 1940 a period with much lower than "normal" volcanic activity. Since the climate science community "picks" circa 1900 as the end of the LIA, they think "normal" is about 0.4C lower than I do, even though their modeled forcing tends to agree with me. 0.4 C is about half of the estimated AGW claimed which makes some of their projected impacts a bit hard for me to swallow.
Looking at the entire Crowley and Unterman 2013 NH data it seems perfectly reasonable to assume that more volcanic activity would lead to lower than normal temperatures and less would lead to warmer than normal temperatures. What really is normal though would depend on what is "normal" volcanic activity .