CMSIS driver for my ARM Cortex M4 STM32L1xx Series MCU?
Use the SPL for your series MCU. CMSIS is included to it.
Path: %dir%\STM32L1xx_StdPeriph_Lib_V1.3.1\Libraries\CMSIS\Device\ST\STM32L1xx and %dir%\STM32L1xx_StdPeriph_Lib_V1.3.1\Libraries\CMSIS\Include

Second option - use STM32CubeL1, but I did not use it and don't know how.