I2C Arbitration lost on ATtiny85
I've looked at this library on GitHub where you got it from and I looked at the TinyWire.h file. This is what it says about the exception that you're receiving.

"
#define USI_TWI_ARBITRATION_LOST 0x0C 
// The master lost the arbitration due to the transmission of another master"

It looks like you're trying to I2C between more than one master when in fact you need a slave. That's how I2C works. Therefore, when you get this error, there's some conflict of interest with your I2C and it won't let one of the masters connect until you have a slave.

I've tried looking at other code to see where the author of this TinyWire library has demonstrated where this exception occurs but I haven't found anything else about it.

EDIT: Wait! I did find something about it... This is in the twi.cpp file.

#ifdef BUS_ARBITRATION
      if(!ack &amp;&amp; (USISR &amp; (1&lt;&lt;USIDC))) { // Check data collision bit
        Twi_slave_init(slaveAddress);
        result.result = 0;
        result.error_code = USI_TWI_ARBITRATION_LOST;
        return result;

Looking at this if statement right here, if there hasn't been acknowledgement from the slave while USISR (which appears to be a variable for a flag) performs an AND operation with USIDC = 0 (USIDC is defined from above) which will always give you zero, it will raise that exception. In other words if there is no acknowledgement from your slave and if the flags are set to zero, you'll get this error.