President Trump was not aware of the unusual arrest of a major Chinese technology executive when he sat down to dinner recently with Chinese President Xi Jinping, according to White House economic adviser Larry Kudlow. Huawei Technologies Chief Financial Officer Meng Wanzhou was arrested in Canada on Dec. 1 on a U.S. extradition warrant. Huawei is suspected of evading American sanctions on Iran, a possibility that U.S. prosecutors have been investigating since 2016. The arrest was made on the same day that Trump and Xi met for dinner amid high-level trade and national security talks in Buenos Aires. An unnamed...